The large scale use of oil in the frying process in snack bars, restaurants, pastry shops, etc. is widely known and, for this reason, there a need to extend the use of the oil and assure the quality of same and foodstuff as well.
As an example of the state of the art, mention is made to patent application U.S. Pat. No. 7,052,605 of Oct. 5, 2001, that discloses a liquid purifying device that also can be used for oils. The device is composed of three parts that are assembled at the time it is used and provided with two inner filtering chambers. The device pumps the oil into a pre-chamber wherein a pre-filtering step is carried out for the purpose of separating solids, and then the oil is transferred to the second chamber wherein a second filtering step is carried out, and finally returned to an oil tub/vat, thus exposing the liquid partially above the oil level.
However, said filter presents a number of drawbacks, viz:                a bad quality filtering action due to deficiency of the filter;        exposure of the oil at the time it is returned after the filtering process;        need to assemble the three parts so that it is able to operate;        need to perform a pre-filtering step for retaining higher particulates in view of the deficiency of the paper filter of the second step that is more suited to retain fine particulates.        
Therefore, one of the objects of the present invention is to provide a robust easy-to-clean portable filtering device. It can be handled quite simply, automatically, and requires very little intervention by the operator.